An essential component of Injections preserved in multiple-dose containers is the antimicrobial agent or antimicrobial agents present to reduce the hazard of having introduced, in the course of removing some of the contents, accidental microbial contamination of the contents remaining. It is a Pharmacopeial requirement that the presence and amount added of such antimicrobial agent(s) be declared on the label of the container. This general chapter provides methods for the most commonly used antimicrobial agents. These methods or other suitably validated methods are to be used to demonstrate that the declared antimicrobial agent is present but does not exceed the labeled amount by more than 20%.